(USA Today) -- Three people are missing after a massive mudslide in western Colorado that is estimated to be 250 feet deep in many places.
Mesa County officials say the mudslide is 2 miles wide and 4 miles long. Deputies describe the area as very unstable, and estimate that an entire ridge has been sliding for most of Sunday.
"This slide is unbelievably big," said Lt. Phil Stratton with the Mesa County Sheriff's Office.
The Plateau Valley Fire Department responded after a witness called into dispatch after hearing a noise that sounded like a freight train that is attributed to the slide.
The area is very remote and no structures have been reported damaged so far. I-70 is approximately 26 miles north of the slide and has not been affected.
Rain has fallen in Mesa County most of the day and likely contributed to the cause of the slide. Officials urged citizens not to go into the area. A road block has been established at the intersection of Highway 330 and Salt Creek Road, outside the town of Collbran for safety.